The structural intensity of shells structure was analyzed based on finite element method (FEM) in this paper. The expressions of structural intensity of plate in FEM were given under harmonic excitation. By using coordinate transformation, mathematical expressions of the structural intensity of shells structure in FEM were deduced. The structural intensities of a rectangular plate and combined structure of tube and plate were calculated. The vector plots of structural intensity under different excitation frequencies were analyzed. The results show that the structural intensity under different frequencies are different, the vector plots present directly the distribution and propagation of energy in shells structure.